Boat



Feb. 9, 1943. R. M. wdc bs ,380

BOAT

Filed May 22, 1941 s Sheets-Sheet 1' INVE NTOH ATTORNEY Feb. 9, 1943. R. M. WOODS 2,310,380

' BOAT Filed May 22, 1941 3 Sheets-Sheet 2 o ATTORNEY Feb. 9, 1943. R. M. wooDs 2,310,380

' BOAT Filed May 22, 1941 3 Sheets-Sheet 5 awe/WM Patented Feb. 9, 1943 UNITED STATES rATEN'r orrlce BOAT Robert M. Woods, Wheeling, W. Va.

Application May 22, 1941, Serial No. 394,588

6 Claims.

This invention relates broadly to water craft, and more particularly to a novel design of boat.

The boat structure and design of the invention has decided advantages over present water craft. These advantages include greater speed; greater stability; less visibility to enemy craft in the case of warfare; easier penetration of water during movement; greater propeller thrust; lower wave, head, skin and wind resistance; easier steering without the use of rudders; ready maneuverability, and greater efficiency generally.

With these and other objects in view, the invention resides in the features of construction which will hereinafter be described, reference being had to the accompanying drawings, in which Figure 1 is a side elevational view of a boat constructed in accordance with the invention;

Figure 2 is a top plan view of the same;

Figure 3 is a front view of the same;

Figure 4 is an enlarged longitudinal sectional view of one of the pontoons;

Figure 5 is a top plan view of a modified form of the invention;

Figure 6 is a front View of the modification shown in Fig. 5;

Figure '7 is a diagrammatic view of the boat constructed in accordance with the invention, this view being intended for the purpose of explanation of the theories and factors involved and,

Figures 8, 9 and 10, are plan, side and end elevations, illustrative of weight shifting mechanism for shifting the center of gravity in boats constructed in accordance with the invention.

Referring, first, to Figures 1, 2 and 3 of the drawings, the reference numeral designates the hull of the boat. A pontoon 2| is rigidly attached to the fore part of the deck, while another pontoon 22 is rigidly supported on a fin 23 adjacent the stern of the boat. A propeller 24 is attached to the drive shaft 25 and is actuated bv an appropriate engine (not shown) housed within the hull.

Appropriately located in the hull of the boat is a weight or a system of weights 26. The primary purpose of the weight system is to maintain the craft in a state of equilibrium, and it is intended that, when desired, the center of gravity of the craft may be altered by simply shifting the weight system either longitudinally, transversely or vertically to correspondingly change the center of gravity and accordingly trim the boat and place the craft in a state of equilibrium.

For purposes of illustration, but not claimed herein, means for such universal shifting of the weight or weights are shown in a conventional manner in Figures 8 to 10, inclusive. It will be seen that Weight 26 may be shifted longitudinally, transversely or vertically by means of turning the hand wheels 262, 262? or 261) respectively, and the screw shafts associated therewith, or in anydesired conventional way not disclosed or claimed in this application.

Due to the very low viscosity of water and the high viscosity of air, it is desirable, in order to obtain the maximum efi'iciency, that the major portion of the hull be submerged. Moreover, it is desirable that the major portion of the hull be submerged for the reason that the portion exposed above the water line governs the amount of wave, windand head resistance to be encountered. Likewise, it is desirable to locate the propeller as deeply as possible so that it will act on water of greater pressure and thus exert the maximum forward thrust. When loaded with cargo, the boat will be submerged to substantially the point indicated in Figure 7 of the drawingsf When empty, or not fully loaded, or when fully loaded with light weight material, the hull will, of course, ride higher above the water line.

The h'ull preferably has a shape substantially corresponding to that illustrated in the drawings and comprises a tapered nose 27; a flat surfaced bow 28 curved rearwardly and downwardly from the tapered nose to the bottom 29; a deck 30 and a substantially tapered stern portion 31. The hull is comparatively narrow and is uniformly reduced in thickness from bow to stern, as shown in Figure 2.

Due to the pressure of water increasing with its depth, the following points become apparent:

l. The forward thrust, due to the rotation of the propeller, is not exerted in line with 5 the center-line of the propeller or its shaft, but is directedupwardly and angularly, as shown at F in Fig. 7.

2'. The forwardmost point, or nose, 21 of the hull should be high so as to be located in the region of low pressure, shown at P in Fig. 7. Thus, the initial penetration of the water is affected in a region where there is a minimum of resistance.

3. As hereinbefore stated, the propeller 23 should be located as deeply as possible in the region of maximum water pressure so as to exert the maximum forward thrust.

The center of gravity of the craft is preferably located at a low point to insure stability. The important feature of the invention, however, is

that the boat can be maintained in the desired state of equilibrium when it is in motion, as well as when it is at rest, by manipulation of the weight system 25 to adjust the location of the center of gravity. In other words, the locale of the center of gravity will differ at times depending upon whether the boat is empty or fully loaded, and whether the cargo consists of heavy, or bulky, but light, material. Moreover, the locale of the center of gravity is dependent upon the distribution of the weight of the cargo. When once loaded and under way, the weight system 26 is manipulated and fixed to change and set the locale of the center of gravity to trim the craft and place it in equilibrium. This equilibrium will be maintained during movement without further adjustment and the reason therefor'can be explained by a study of the illustration. of Figure. 7 of the drawings. The summation of all forces opposing forward motion I to V1, inclusive, multiplied by their respective moment arms about, the center of gravity of the boat as awhole'; plus F multiplied by its moment arm about the center of gravity of the boat; plus the frictional forces 1 to 16, inclusive, multipliedby their respective moment arms about the center of gravity of the boat are all equal; to zero. Consequently, equilibrium in motion results.

Should the center of gravity be lowered by manipulation of the weight system 26, the boat would nose under the water. Conversely, were the center of gravity raised, the nose 2'! would be elevated above the water level. In either case, the cross sectional area being forced through the water would be increased with theresultant loss of efficiency.

Likewise, with the. center of gravity remaining in its-original position, changing. the angleiof the center-line.- of' the propeller would cause similar results. In other words, if the rear end of. the propeller were lowered, the-boat would nose down ward, and were the rear end of the propeller elevated, the nose would be raised above water level.

It will now be: understood that the boat can be put into'equilibrium at any time for varying loads. After the; boat is placed in equilibrium, a slight force or weight exerted either on the bow or stern will disturb the desired horizontal balance, and, further, a force exerted downward at the center of gravity would submerge the boat. The two pontoons 2| and 22' are provided to overcome this objection. The fore pontoon 2| is; larger than the aft pontoon 2-2 in. proportion to the distance of its location from the center of gravity of the craft. The pontoons are hollow and function to stabilize the boat. It. is desired that at least one of the pontoons be provided with a hatch 3,2.

The problem of operating the boat inheavy seasremains. Due to the low lines of the craft, a large wave would inundate the boat. Thus, the question of water getting into the boat arises, as. well as supplying the interior with. air. Because the period of time during which this inundati'on occurs is brief, the logical: system is one. utilizing time lag; Additionally, since the hydraulic head of pressure over-the top of the submerged pontoon is relatively small,, it is advisable to provide resistance to, the. entrance of water.v The problem. issolved by providing ports 33: in the. lower casing wall of the-pontoonsand connecting to each. of said ports a. vertically extending reversely'bent breather tube. 34. Such an arrangement discourages. the entrance. of

water interiorly of the craft and permits the.

water to quickly drain from the tube once the wave is past. It might also be pointed out that, even in an unusually rough sea, at least one of the pontoons would not be submerged.

The propeller 24 is preferably of helical shape, the curve being generated from a circle spaced off for a simple harmonic curve.

If the craft were equipped with a gun in one of the pontoons, the recoil after firing is to be considered. In the longitudinal axis, the pontoons would offset the recoil effect. However, the recoil would jeopardize the transverse stability of the boat. This transverse stability problem is solved by the modified form of the invention illustrated in Figs. 5 and 6 of the drawings. Such a modified form comprises two similarly constructed boats 35 joined together by a web 36 in which a shiftable weight 31 is provided.

The firing of the gun would produce a recoil effect on the pontoon in which the gun is located. Such recoil would partially submerge this pontoon, but such submersion would be resisted by the opposite pontoon which would, as a consequence, be lifted partially out of the water. Thus; the weight of the last mentioned elevated pontoon and the force of gravity would prevent serious stablity disturbance and would quickly restore any slight disturbance which might be caused by the recoil.

The weight 31 may be shifted transversely to alter the center of gravity transversely for the purpose of steering the boat by this means and without the use of a rudder. Likewise, the form of the invention illustrated in Figs. 1, 2 and 3 may, if desired, be steered by transverselyshifting its, weight 26, but this form of steering is especially adapted to the character of boat shown in Figs. 5 and 6 because it affords greater maneuverability when used in connection with the dual-type craft.

What is claimed is:

1. A boat including a substantially streamlined hull, said hull characterized by having a main body portion with a horizontal deck, a pointed nose extending forwardly from the upper part of the main body portion and normally adapted to be in a slightly submerged position. the forward portion of the main body of the hull presenting a laterally extending surface curved downwardly from the forward tip of the pointed nose to the bottom of the main body portion of the hull at a point substantially below the forward portion of the deck, the rear of the main body portion of the hull sloping downwardly from said deck to a submerged point forming the rear end of the hull in a plane substantially with the bottom of the main body portion of the hull, and propeller means extending rearwardly from said submerged rear end portion of the hull.

2. A boat including a substantially streamlined hull, said hull characterized by having a main body portion with a horizontal deck,apointed nose extending forwardly from the upper part of the main body portion and normally adapted to be in a slightly submerged position, the forward portion of the main body of the hull presenting a laterally extending surface curved downwardly from the forward tip of the pointed nose to the bottom of. the main body portion of the hull at a point substantially below the forward portion of the deck, the rear of the main body portion of the hull sloping downwardly from said deck to a submerged point forming a the rear end of the hull in a lane substantially vertically, longitudinally and transversely of the hull to change the center of gravity.

4. A marine construction comprising twin substantially streamlined screw-propelled hulls, arranged side by side, and a hollow web extending horizontally and providing a communicating connecting link between the two hulls, said web having a substantially streamlined formation and normally in a submerged position.

5. A marine boat construction adapted to be equipped with guns and the like comprising, twin substantially streamlined screw-propelled hulls arranged side by side, a hollow web extending horizontally and providing a communicating connecting link between the two bulls, and a transversely shiftable ballast means in said hollow web.

6. A marine construction including a streamlined hull having a bow and stern, propelling means for the hull positioned on the stem at a point below the horizontal plane of the foremost part of the bow so that the thrust forces produced by said propelling means are exerted above the center of gravity of the hull, the bow of said hull having a contour to substantially equalize the upward thrust forces of the propelling means above the center of gravity, and means for shifting the center of gravity of the hull so that the summation of said thrust forces about the center of gravity is equal to zero when the hull is at rest or in motion.

ROBERT M. WOODS. 

